Method and Device for Performing Alternating Chest Compression and Decompression

ABSTRACT

A plunger adapter and a detachable compression pad for piston driven chest compression devices optimizes the application of chest compressions to a fixed location on a patient&#39;s chest. The detachable compression pad may be removably secured to the patient above the patient&#39;s sternum to ensure that the compression pressure from the piston through the piston adapter is applied to a fixed location on the patient&#39;s chest. As the plunger and plunger adapter retract from the chest, the compression pad remains fixed to the patient&#39;s chest, and as the plunger and plunger adapter extend from the chest compression unit for subsequent compression strokes, the distal end of the plunger adapter reengages the compression pad to apply compression to a fixed location on the patient&#39;s chest.

This application is a continuation of U.S. patent application Ser. No.13/631,289 filed Sep. 28, 2012, now U.S. Pat. No. 8,920,348.

FIELD OF THE INVENTIONS

The inventions described below relate the field of cardiopulmonaryresuscitation (CPR).

BACKGROUND OF THE INVENTIONS

According to the American Heart Association nearly 383,000out-of-hospital sudden cardiac arrests occur annually in the UnitedStates. These patients may be saved by the timely application of lifesaving measures such as Cardiopulmonary resuscitation (CPR).

CPR is a well-known and valuable method of first aid used to resuscitatepeople who have suffered from cardiac arrest. CPR requires repetitivechest compressions to squeeze the heart and the thoracic cavity to pumpblood through the body. Artificial respiration, such as mouth-to-mouthbreathing or a bag mask device, is used to supply air to the lungs. Whena first aid provider performs manual chest compression effectively,blood flow in the body is about 25% to 30% of normal blood flow.However, even experienced paramedics cannot maintain adequate chestcompressions for more than a few minutes. Hightower, et al., Decay InQuality Of Chest Compressions Over Time, 26 Ann. Emerg. Med. 300(September 1995). Thus, CPR is not often successful at sustaining orreviving the patient. Nevertheless, if chest compressions could beadequately maintained, then cardiac arrest victims could be sustainedfor extended periods of time. Occasional reports of extended chestcompression efforts (45 to 90 minutes) have been reported, with thevictims eventually being saved by coronary bypass surgery. See Tovar, etal., Successful Myocardial Revascularization and Neurologic Recovery, 22Texas Heart J. 271 (1995).

In efforts to provide better blood flow and increase the effectivenessof bystander resuscitation efforts, various mechanical devices have beenproposed for performing AUTOMATED CHEST COMPRESSIONS. There arecurrently two types of automated chest compression devices. One typeuses a belt placed around the patient's chest to effect chestcompressions. The AutoPulse® chest compression is one such device, andis described in patents such as Mollenauer, et al., Resuscitation Devicehaving a Motor Driven Belt to Constrict/Compress the Chest, U.S. Pat.No. 6,142,962 (Nov. 7, 2000). The other type uses a piston whichrepeatedly compresses the chest. Piston based chest compression systemsinclude the LUCAS® chest compression device (illustrated in Sebelius, etal., Rigid Support Structure on Two Legs for CPR, U.S. Pat. No.7,569,021 (Aug. 4, 2009)) and the THUMPER® chest compression device(illustrated in Barkolow, Cardiopulmonary Resuscitator Massager Pad,U.S. Pat. No. 4,570,615 (Feb. 18, 1986). These chest compression systemsinclude a piston and a motor for repeatedly driving the pistondownwardly on the chest, and lifting the piston from the chest to allowthe chest to expand under its own natural resistance. Some have proposedimproving piston-based CPR with a technique called activecompression/decompression, which involves actively lifting the chestwall between CPR compressions. Sebelius, et al., Positioning Device ForUse In Device For Treating Sudden Cardiac Arrest, U.S. Pat. No.7,841,996 (Nov. 30, 2010) proposes use of a suction cup on the bottom ofthe piston, to secure the chest of the patient to the piston. In thismanner, the piston, upon upward movement, actively lifts the patient'schest, or at least exerts some upward force on the anterior wall of thechest, to speed the expansive of the chest between each compression. Amanual CPR assistance device, the RESQPUMP®, (Advanced CirculatorySystems), also includes a suction cup on the bottom of a manuallyoperated compression pad. This is also proposed to provide liftingforce, through the suction cup, on the anterior surface of the chestduring the upstroke of the compression cycle.

SUMMARY

The devices and methods described below provide for improved attachmentof a compression pad of a piston-based chest compression device to apatients chest, to provided improved active compression/decompressionCPR. The device includes a compression pad for piston driven chestcompression devices that enables and optimizes compression anddecompression force. The compression pad includes two or more suctioncups, vacuum cups or suckers to engage the surface of the patient'schest and provide improved decompression force to the patient's chestduring mechanical CPR.

When the rim or distal edges of the suction cups are pressed against thesurface of the patient's chest and the proximal ends of the suction cupsare pressed during chest compression, the volume of the space within thesuction cup and the chest surface is reduced, which causes the fluid,air, between the cup and the chest to be expelled past the rims of thesuction cups. When the chest compression device ends its compressionstroke and is pulled upward in the decompression stroke, suction createdbetween the suction cups and the chest helps secure the compression padto the chest. As the material of the compression pad tends to resume itsoriginal shape when lifted, and some air has already been forced out ofthe space inside of the cups, the pressure in each of the suction cupspaces is lower that atmospheric pressure which enables the compressionpad to exert some decompression force on the patient's chest. Thepressure difference between the atmosphere on the outside of the cup iswhat keeps the cup adhered to the surface and enables decompressionforce to be exerted on the patient's chest.

The upward force developed by a suction cup is a function of the area ofthe suction cup. Using multiple suction cups on a compression padenables the pressure of each suction cup to be kept low while thecombined decompression force of all the suction cups of a compressionpad is high enough to provide meaningful chest decompression. Balancingthe suction force of multiple small suction cups against the total forcefor all the suction cups on a compression pad eliminates injury to apatient's chest that may occur with a single large suction cup. Thesuction cups may adopt any useful shape to optimize the number ofsuction cups on a compression pad and to optimize the decompressionforce on a patient's chest as well as optimizing the application ofcompression force to the patient's chest. Also, the use of numerous,small suction cups facilitates conformance of the suction cups tocomplex 3-D shapes such as the surface of the patient's chest. Improvedsurface conformance results in improved sealing of the suction cups tothe patient's skin, further enhancing the amount of upward force thatcan be applied by the device. Multiple suction cups on the distal sideof the compression pad enables the decompression force applied by theretraction of the plunger adapter to be limited to prevent dissectinginjury to the tissues of a patient's chest.

A compression orientation pad may be secured to the patient's chest toprovide a readily visible landmark for applying the chest compression,to provide a smooth surface for achieving suction to enabledecompression force to be applied, and to incorporate ECG anddefibrillation electrodes and other suitable rescue components.Alternatively, any smooth sticker or adhesive sheet may be used as alandmark and to provide a smooth surface for optimizing the suction ofthe compression pad against the patient's chest.

To provide a controllable mechanism for applying upward force on thepatient's chest, a detachable plunger adapter and a cooperatingcompression pad adhered via suction to the patient's chest may be used.Detachment mechanisms between the plunger adapter and the compressionpad which can be readily limited in the amount of upward force whichmight be applied include magnetic or frictional attachment between thecompression pad and the adapter. The attachment force between theplunger adapter and the compression pad can thus be predetermined andlimited.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a piston driven chest compression device witha suction compression pad and a cross section of a patient's chestshowing landmark skeletal structures.

FIG. 2 is a cross section of the chest compression device of FIG. 1taken along A-A with a separable plunger adapter and compression pad.

FIG. 3 is an end view of the distal end of the compression pad of FIG.1.

FIG. 4 is an end view of the distal end of an alternate compression padfor the device of FIG. 1.

FIG. 5 is an end view of the distal end of another alternate compressionpad for the device of FIG. 1.

FIG. 6 is a perspective view of a piston driven chest compression deviceengaging a patient with an orientation and defibrillation pad.

FIG. 7 is a perspective view of a piston driven chest compression devicewith the compression pad of FIG. 4.

FIG. 8 is a perspective view of a piston driven chest compression devicewith the proximal end of the compression pad including multipleintegrated suction cups.

FIG. 9 is a side view of a plunger adapter and compression pad.

FIG. 10 is an end view of the distal end of a plunger adapter with afrusto-conical socket.

FIG. 11 is an end view of the proximal end of a compression pad with anextension corresponding to the frusto-conical socket of the plungeradapter of FIG. 9.

FIG. 12 is an end view of the distal end of the compression pad of FIG.9.

FIG. 13 is a side view of an alternate plunger adapter and compressionpad.

FIG. 14 is an end view of the distal end of the plunger adapter of FIG.13.

FIG. 15 is an end view of the proximal end of a compression pad with anextension corresponding to the plunger adapter of FIG. 13.

FIG. 16 is an end view of the distal end of the compression pad of FIG.13.

FIG. 17 is a perspective view of a piston driven chest compressiondevice with a multi-lobed compression pad engaging a patient with anorientation and defibrillation pad.

FIG. 18 is an end view of the distal end of the compression pad of FIG.17.

FIG. 19 is an end view of the distal end of an alternate multi-lobedcompression pad.

FIG. 20 is a side view of the compression pad of FIG. 19.

FIG. 21 is a perspective view of an alternate compression pads with fiveappendages.

FIG. 22 is a perspective view of another alternate compression pad withthree appendages.

DETAILED DESCRIPTION OF THE INVENTIONS

FIGS. 1 and 2 illustrate a piston-based chest compression deviceinstalled on a patient. In FIGS. 1 and 2, mechanical chest compressiondevice 10 is oriented to apply compressions to the anterior surface ofchest 2 of patient 1. Chest compression device 10 includes supportstructure 11 which supports and orients chest compression unit 12apposing sternum 2A. Support structure 11 may be subdivided into legs11A and 11B and back plate 11C. Chest compression unit 12 includes anysuitable drive means such as motor 13 which may be a reversibleelectromotor, a linear actuator or the like. Plunger 14 has a distal end14D and a proximal end 14P, and proximal end 14P of the plunger isoperably coupled to motor 13. The plunger extends from and withdrawsinto the housing upon operation of motor 13, and the distal end 14D ofplunger impacts the patient's chest. A motor control unit such ascontroller 15 is operably connected to motor 13 and may include amicroprocessor to control the operation of the motor and the plunger. Acompression pad 17 (referred to as a compression component by Sibelius)with two or more suction cups 19 applies compression and decompressionforce to patient 1.

Alternatively, support structure 11 may also have a single leg or postwhich supports a chest compression unit cantilevered over the patient.

In use, compression pad 17 is removably secured to the patient's chestat force application location 18, which is in a superior positionrelative to sternal notch 2N as illustrated in FIG. 2. Compression pad17 may be secured to the patient by suction created by the suction cups19 formed on distal end 17D. The mechanical chest compression device 10is oriented around the patient's chest 2 with chest compression unit 12apposing compression pad 17. Plunger 14 is extended to confirm propersiting of compression pad 17 on the patient and to confirm mating andorientation of plunger adapter 16 with compression pad 17. Uponconfirmation of proper alignment and orientation, controller 15 isinstructed, through any suitable interface such as interface 12A, toperform cyclic compressions and decompressions for CPR.

Distal end 17D of compression pad 17 may adapt any suitable number andconfiguration of suction cups as illustrated in FIGS. 3, 4 and 5.Compression pad 20 includes suction cups 22 which are generally the samesize and shape and oriented to maintain cup rims 23 in rim plane 24. Rimplane 24 may be curved and may adopt any suitable shape to optimizesuction for each of cups 22. Compression pad 27 may include many smallsuction cups, such as suction cups 28, to control the amount of suctionprovided by any single suction cup and to minimize the likelihood thatloss of suction by any single suction cup will eliminate thedecompression force of the chest compression device. Alternatecompression pad 30 illustrates a combination of sizes and shapes ofsuction cups such as round suction cups 31, oval suction cups 32 andsmall suction cups 33 to provide a controlled and predictable amount ofdecompression force. Multiple suction cups and the use of small sizesuction cups permits the compression pad and the suction cups to conformto complex 3-D surfaces and it also prevents loss of suction by thesuction cups at areas of varying or uneven contour on the patient'schest such as occur in the area of the sternal notch.

Chest compression and decompression performed by mechanical chestcompression device 10 may incorporate compression orientation pad 40.Compression orientation pad 40 may be configured to perform multiplefunctions and include additional elements such as ECG electrodes 41 aswell as defibrillation pads 42 as well as any other suitable components.Compression orientation for chest compression device 10 is provided bycompression target 43 which is secured to location 18 by a rescuerbefore initiation of mechanical chest compression/decompression.Compression orientation pad 40 is secured to the patient's chest usingany suitable adhesive such as adhesive 45 forming a layer between pad 40and chest 2. Compression orientation pad 40 may be formed of one or morelayers such as layer 46 which provides structural strength anddistributes the compression/decompression forces to the entire area ofcompression target 43. Sections of pad 40 such as compression target 43may have additional layers such as top or upper layer 47 which includesa resilient and smooth, surface 47X to optimize the formation of suctionin the suction cups of the compression pad used, such as the deviceillustrated in FIG. 7. Mechanical chest compression device 50 includescompression pad 52 with three round suction cups 53 formed on distal endof the compression pad. Compression orientation pads may includecompression targets sized and configured to accommodate variousconfigurations of compression pads such as those illustrated in FIGS. 3,4, 5, 7 and 8.

An alternate configuration of suction cups is illustrated in FIG. 8.Mechanical chest compression device 60 includes compression pad 62 withone or more irregularly shaped suction cups 63 and one or more circularsuction cups 64 formed on distal end of the compression pad.

Compression pads with two or more suction cups may be readily combinedwith cooperating plunger adapters and compression pads as disclosed inour copending U.S. patent application Ser. No. 13/629,434 filed Sep. 27,2012 which is incorporated herein by reference in its entirety.

To limit the application of excessive decompression force to the chestof a patient undergoing mechanical chest compressions, a separateplunger adapter and compression pad may be used. In FIGS. 9, 10, 11 and12, plunger adapter 70 has a height or anterior posterior dimension 70Dand compression pad 71 has a height or anterior posterior dimension 71D.Proximal end 70P of plunger adapter 70 is removably secured to distalend 72D of plunger 72 using any suitable technique such as matingthreads, keyed slots, friction engagement such as socket 70S engagingplunger distal end 72D or any other technique. The height of a plungeradapter and the height of a compression pad may be individually selectedto conform to the anterior posterior dimensions of a patient and thelength and extension capability of a plunger and compression unit.Compression pad 71 includes extensions such as extension 73 sized toengage a comparably sized socket such as socket 74 in any suitableplunger adapter such as plunger adapter 70. The inner surfaces, surface74A and surface 74B, of a plunger adapter socket such as socket 74 mayinclude an adhesive or coating such as adhesive layer 75 with apreselected level of adhesion to maintain a limited engagement between aplunger adapter, such as adapter 70, and a compression pad such ascompression pad 71, to produce a preselected level of decompressionduring each retraction of the plunger while performing automated chestcompressions to limit or eliminate damage to the patient. Adhesive layer75 may also be applied to compression pad surfaces 73A and or 73B.

Compression pad 71 is a generally incompressible pad configured to adaptto the shape of the patient's chest. A compression pad such ascompression pad 71 may be formed of one or more layers such as firstlayer 71A and second layer 71B to optimize the application ofcompressive force to the patient. The proximal or upper end of thecompression pad is a generally hard extension or socket such asextension layer 73 for engaging the plunger adapter. The first orcentral layer, layer 71A may be a flexible and incompressible layer toconform to the shape of the patient's chest. The lower or distal end,second layer 71B, of the compression pad is flexible to adapt to theshape of the patient's chest and may include one or more flexible cups,suction cups 76, for creating one or more areas of vacuum between thecompression pad and the patient's chest in suction cup volume 77. Whenthe rim or distal edge 76D of the suction cups are pressed against thesurface of the patient's chest, a sticker or other pad and the proximalends of the suction cups are pressed during chest compression, thevolume of the space, suction cup volume 77, within the suction cup andthe chest or sticker surface is reduced, which causes the fluid, air,between the cup and the chest to be expelled past the rims of thesuction cups. When the chest compression unit ceases to applycompression force and begins the decompression phase of the mechanicalCPR process, the material of the compression pad tends to resume itsoriginal shape. Because some or all of the air has already been forcedout of suction cup volume 77, the pressure in each of the suction cupspaces is lower that atmospheric pressure which enables the compressionpad to exert some decompression force on the patient's chest. Thepressure developed by a suction cup is a function of the area of thesuction cup. Using multiple suction cups on a compression pad enablesthe pressure of each suction cup is kept low while the combineddecompression force of all the suction cups of a compression pad is highenough to provide meaningful chest decompression. Using 10 or moresuction cups enables balancing the suction force of multiple smallsuction cups against the total force for all the suction cups on acompression pad eliminates injury to a patient's chest that may occurwith a single large suction cup.

Any suitable smooth sticker sheet or pad such as compression orientationpad 40 or sticker 78 may be removably adhered to a patient's chest toprovide smooth surface 78A to optimize the suction between each suctioncup and the sticker sheet.

Suitable engagement mechanisms may be included in the plunger and theplunger adapter to provide a preselected level of chest expansion forcein addition to chest compression force. A magnet may be provided in thedistal end of the plunger and a corresponding magnet or ferrous materialmay be included in the proximal end of the plunger adapter to provide apreselected retention force between the plunger and the plunger adapter.The retention force is selected to provide some expansion force to thepatient's chest between compressions without applying enough expansionforce to the patient's chest to tear the patient's skin or underlyingtissue. Similarly an electromagnet may be provided in distal end of theplunger to provide an adjustable level of retention force, or to providetimed release of the plunger adapter from the plunger.

As illustrated in FIGS. 13, 14, 15 and 16, plunger adapter 80 includessocket 81 that is sized and dimensioned to engage extension 82 ofcompression pad 83. Compression pad 83 includes suction cups of varyingsizes and configurations such as first suction cups 84, second suctioncups 85 and third suction cups 86. The relative sizes, orientation andcombinations of sizes and orientation of the suction cups is selected tooptimize the compression force, the decompression force provided by thecompression pad.

To generate a predetermined decompression force 87 during the retractionof plunger 88, magnets such as adapter magnet 80M and compression magnet83M may be included in plunger adapter 80 and compression pad 83 toprovide the predetermined retention force, such as force of attractionor magnetic force 89, to hold compression pad 83 to plunger adapter 80until the predetermined decompression force is exceeded. Thepredetermined level of decompression force is selected to be at a levelbelow which, the chest tissue at force application location 19 will notbe damaged before compression pad 83 releases from plunger adapter 80.Any other suitable technique for providing a predetermined level ofretention force 89 may be used such as electromagnetic attraction,frictional engagement or others. Any other suitable cooperativeconfigurations of socket and extension may be used.

A compression pad such as compression pad 90 of FIGS. 17 and 18 mayadapt any suitable complex shape such as shape 91 with multipleappendages, arms or lobes 92. Distal end 90D of compression pad 90contain numerous suction cups 94. The use of multiple lobes enables acompression pad with many suction cups to conform to the irregular andcomplex three-dimensional shapes of patient chest surfaces. Multiplelobes 92 are conformable and inelastic to convey the decompression forcebetween mechanical chest compression device 95 and the anterior surface2 of the patient's thorax 3, or any sticker or pad adhered to thepatient's chest such as compression orientation pad 40. Arms or lobes 92should be secured to the patient, no lower than the inferior margin ofthe ribcage and generally constrained to the skin superficial to theanterior surface of the ribcage.

Compression pad 100 of FIGS. 19 and 20 has an irregular shape 101 withfive lobes 102. Compression pad 100 includes rigid pad 103 on proximalend 100P to apply compressive force to the patient's chest whileflexible and inextensible lobes 102 optimize the application ofdecompression force to a patient. Distal end 100D includes a multiplesuction cups 94 of generally similar size and shape, evenly distributedover the distal end.

As illustrated in FIGS. 21 and 22, compression pads may adopt anysuitable shape with two or more lobes. Compression pad 106 of FIG. 21includes five lobes with lobes 107A and 107B having a different size andshape from lobe 107C, which is again different from lobes 107D and 107E.Depending on the length and flexibility of the lobes, compression padsmay include a rigid pad 108 to transfer compression energy from plunger109 to the patient.

Compression pad 110 of FIG. 22 includes three lobes and each lobe suchas lobe 111 may have a different size and shape from lobe 112 which mayalso be different than lobe 113. The lobes may be rotationally orientedor clocked in any suitable orientation 114 to optimize the compressionand decompression forces applied to the patient.

While the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Theelements of the various embodiments may be incorporated into each of theother species to obtain the benefits of those elements in combinationwith such other species, and the various beneficial features may beemployed in embodiments alone or in combination with each other. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. A method of performing chest compression and decompressionon a patient comprising the steps: providing a mounting structuresurrounding the patient's chest; securing a chest compression unit onthe mounting structure apposing the patient's sternum, the chestcompression unit including a reversible motor, a plunger having a distalend and a proximal end, the proximal end of the plunger operably coupledto the reversible motor, the distal end of the plunger extending fromand withdrawing into the housing to perform chest compression on thepatient; providing an motor control unit operably connected to the motorto control the motor and the plunger; providing a compression pad overthe sternum of a patient, the compression pad having a distal end and aproximal end, the proximal end engaging the plunger and the distal endhaving a two or more suction cups formed therein; and initiating cyclicchest compressions and decompressions through the motor control unit. 2.The method of claim 1 wherein the motor control unit further comprises amicroprocessor.
 3. The method of claim 1 further comprising the steps:providing a plunger adapter secured to the distal end of the plunger;wherein the proximal end of the compression pad removably engages theplunger adapter.
 4. The method of claim 3 wherein the plunger adaptercomprises: a generally cylindrical adapter with a proximal end and adistal end, the proximal end removably engaging the distal end of theplunger, the distal end of the plunger adapter having a frustoconicalsocket for engaging the compression pad; and wherein the compression padfurther comprises a frustoconical extension for removably engaging thedistal end of the plunger adapter.
 5. The method of claim 3 wherein theplunger adapter comprises: a generally cylindrical plunger adapter witha proximal end and a distal end, the proximal end removably engaging thedistal end of the plunger, the distal end of the plunger adapter forengaging the compression pad; and wherein the compression pad furthercomprises a generally cylindrical socket for removably engaging thedistal end of the plunger adapter.
 6. The method of claim 3 wherein thecompression pad includes 10 or more suction cups.
 7. The method of claim3 wherein the two or more suction cups are at least two different sizes.8. The method of claim 3 wherein the two or more suction cups have atleast two different shapes.
 9. An improved chest compression device ofthe type with a chest compression unit, a mounting device for mountingthe chest compression unit on a patient, the chest compression unitcomprising a housing, a plunger having a distal end and a proximal end,the proximal end of the plunger disposed in the housing, a reversiblemotor, a mechanical device connected from the motor to the proximal endof the plunger for driving the plunger in a reciprocating manner withrespect to the housing and for translating rotational motion of themotor to linear motion of the plunger, an motor control unit connectedto the motor and including a microprocessor, a first monitor operablefor monitoring the position of the plunger in respect of the housing, asecond monitor operable for monitoring the position of the plunger inrespect of the mechanical device for translating rotational motion tolinear motion or the rotor, the positions monitored by the first andsecond monitors being communicated to the motor control unit, whereinthe improvement comprises: a compression pad with a distal end and aproximal end, the proximal end engaging the plunger and the distal endhaving a two or more suction cups formed therein.